This invention relates to an image forming apparatus for automatically reading out information on characteristics of a photosensitive recording sheet and performing exposure and development processes on the basis of the information.
A photosensitive recording sheet which has been used in a conventional image forming apparatus has various characteristics such as a photosensitive characteristic, a development characteristic and so on. These characteristics are varied in accordance with a process for manufacturing the photosensitive recording sheet, a raw material for the photosensitive recording sheet, and a kind of the photosensitive recording sheet. Accordingly, photosensitive recording media which have been manufactured by various makers have different characteristics and therefore different optimum conditions for the exposure, development and the other processes from one another. This difference in optimum conditions between the photosensitive recording media requires an user to beforehand input to the image forming apparatus data on the optimum conditions specified by each of the makers manually, for example, using a keyboard. However, the manual operation of the user for inputting the data on the exposure, development and the other processes in the image forming apparatus is very complicated and therefore an input error is easily induced. Accordingly, there is a possibility in the conventional image forming apparatus that an image is not formed.
In view of the above disadvantage of the conventional image forming apparatus, the applicant of this application has proposed a detection mechanism in which a photosensitive recording sheet is provided at a leading end thereof with a leader on which information on the exposure, development and the other characteristics of the photosensitive recording sheet is printed in a bar code pattern, the information on the leader is read out by a sensor and the exposure, development and the other processes are carried out in the image forming apparatus in accordance with the read-out information. In this detection mechanism, the information on the leader is read out at a sheet outlet of a cartridge for accommodating a roll type of photosensitive recording sheet while the photosensitive recording sheet is automatically fed through the sheet outlet. That is, one end of the photosensitive recording sheet, a free end of the leader, is not supported and therefore the leader itself is unstably placed in a read-out region in a read-out operation. Accordingly, a focusing for reading out the information is difficult to be set and there is a possibility that a reading error occurs because of slack or chattering of the leader.